58 



BULLETIN 75, UNITED STATES NATIONAL MUSEUM. 



sand, bottom temperature 35.9, 1 specimen. Bathymetrical range, 

 56 to 625 fathoms. Temperature range, 42.8 to 30.1. One hun- 

 dred and seven specimens. 



Type. Cat. No. 25629, U.S.N.M., from station 3331. 



Although this species is superficially so near leptoctenia that it 

 might easily be mistaken for that species, the four arm spines and the 

 peculiar arm comb easily distinguish quadrispina from that, and from 

 every other near ally. The 107 specimens show very little diversity 

 of structure, though a few have minute disk spines as in leptoctenia. 

 It is a more northern form than that species, as it has not been 

 collected south of 53 55' 30" N. on the American coast nor south of 

 43 on the Asiatic. Its bathymetrical range is also less, 56 to 625 

 fathoms. 



OPHIURA BATHYBIA, new species.a 



Disk 15 mm. in diameter; arms about 65 mm. long. Disk covered 

 with a close coat of numerous small, overlapping scales, many of 



FIG. 14. OPHIURA BATHYBIA. X3.3. a, FROM ABOVE; 6, FROM BELOW; c, SIDE VIEW OF THREE ARM 



JOINTS NEAR DISK. 



which carry very slender spinelets nearly 'a millimeter long; these 

 spinelets are easily rubbed off, but the places of attachment remain 

 more or less clearly indicated as minute pits. Radial shields some- 

 what crescentic, about three times as long as wide, widest at outer 

 end, where they are most nearly in contact, though even there dis- 

 tinctly separate. Upper arm plates tetragonal, at first wider than 

 long, but soon becoming longer than wide, with distal margin more or 

 less convex; in contact the whole length of arm. Interbrachial spaces 

 below closely covered with scales, upon which minute spines are 



a BaObc, signifying deep, an 

 at which it lives. 



, signifying life, in reference to the unusual depth 



